Health Library

Influenza

Influenza (“the flu”) is an infection that affects your respiratory tract (the mouth, nose, and lungs, and the passages between them). Unlike a cold, the flu can make you very ill. And it can lead to pneumonia, a serious lung infection. For some people, especially older adults, young children, and people with certain chronic conditions, the flu can have serious complications and even be fatal.

What Are the Risk Factors for the Flu?

Anyone can get the flu. But you’re more likely to become infected if you:

Have a weakened immune system.

Work in a health care setting where you may be exposed to flu germs.

Live or work with someone who has the flu.

Haven’t received an annual flu shot.

How Does the Flu Spread?

The flu is caused by viruses. The viruses spread through the air in droplets when someone who has the flu coughs, sneezes, laughs, or talks. You can become infected when you inhale these viruses directly. You can also become infected when you touch a surface on which the droplets have landed and then transfer the germs to your eyes, nose, or mouth. Touching used tissues, or sharing utensils, drinking glasses, or a toothbrush with an infected person can expose you to flu viruses, too.

What Are the Symptoms of the Flu?

Flu symptoms tend to come on quickly and may last a few days to a few weeks. They include:

Fever usually higher than 101°F (38.3°C) and chills

Sore throat and headache

Dry cough

Runny nose

Tiredness and weakness

Muscle aches

Factors That Can Make Flu Worse

For some people, the flu can be very serious. The risk of complications is greater for:

Children under age 5.

Adults 65 years of age and older.

People with a chronic illness, such as diabetes or heart, kidney, or lung disease.

People who live in a nursing home or long-term care facility.

How Is the Flu Treated?

Influenza usually improves after 7 days or so. In some cases, your health care provider may prescribe an antiviral medication. This may help you get well sooner. For the medication to help, you need to take it as soon as possible (ideally within 48 hours) after your symptoms start. If you develop pneumonia or other serious illness, hospital care may be needed.

Easing Flu Symptoms

Drink lots of fluids such as water, juice, and warm soup. A good rule is to drink enough so that you urinate your normal amount.

Get plenty of rest.

Ask your health care provider what to take for fever and pain.

Call your provider if your fever rises over 101°F (38.3°C) or you become dizzy, lightheaded, or short of breath.

Ask your health care provider if others in your household should receive antiviral medication to help them avoid infection.

How Can the Flu Be Prevented?

One of the best ways to avoid the flu is to get a flu vaccination each year. Viruses that cause the flu change from year to year. For that reason, doctors recommend getting the flu vaccine each year, as soon as it's available in your area. The vaccine may be given as a shot or as a nasal spray. Your health care provider can tell you which vaccine is right for you.

Wash your hands often. Frequent handwashing is a proven way to help prevent infection.

Carry an alcohol-based hand gel containing at least 60 percent alcohol. Use it when you don’t have access to soap and water. Then wash your hands as soon as you can.

Avoid touching your eyes, nose, and mouth.

At home and work, clean phones, computer keyboards, and toys often with disinfectant wipes.

If possible, avoid close contact with others who have the flu or symptoms of the flu.

Handwashing Tips

Handwashing is one of the best ways to prevent many common infections. If you’re caring for or visiting someone with the flu, wash your hands each time you enter and leave the room. Follow these steps:

Use warm water and plenty of soap. Rub your hands together well.

Clean the whole hand, under your nails, between your fingers, and up the wrists.

Wash for at least 15 seconds.

Rinse, letting the water run down your fingers, not up your wrists.

Dry your hands well. Use a paper towel to turn off the faucet and open the door.

Using Alcohol-Based Hand Cleaners

Alcohol-based hand cleaners are also a good choice. Use them when you don’t have access to soap and water. Follow these steps:

Squeeze about a tablespoon of gel into the palm of one hand.

Rub your hands together briskly, cleaning the backs of your hands, the palms, between your fingers, and up the wrists.

Rub until the gel is gone and your hands are completely dry.

Preventing Influenza in Healthcare Settings

The flu is a special concern for people in hospitals and long-term care facilities. To help prevent the spread of flu, many hospitals and nursing homes take these steps:

Health care providers wash their hands or use an alcohol-based hand cleaner before and after treating each patient.

People with the flu have private rooms and bathrooms or share a room with someone with the same infection.

High-risk patients who don’t have the flu are encouraged to get the flu and pneumonia vaccines.